Cross platform user authentication

[Peter C.S. Adams]

I'm trying to integrate a lab of Macs and a lab of PCs using my Mac OS X
Server and need some advice. Perhaps some of you with cross platform
experience can point me to some readable tutorials (i.e. Written for Mac
users with some Unix experience, not the other way around)? Here's what I
envision:

Upon presenting an ID and signing an acceptable use policy, the user is
assigned (or allowed to create) a username and password.

When they enter the lab, they sit at any idle PC or Mac and log in using
this username and are allowed to use a few megabytes of network storage and
some modest print quota.

When they leave (after some idle time) the computer automatically logs them
out and goes into "guest" mode, which has surfing and typing capabilities
but no printing.

After a semester, or a year, or whatever, their account expires and must be
either re-enable with a new ID and policy document or deleted.

So my questions are:

1. How do I disable printing in Guest mode on the Macs?

2. How do I set "use only these applications" on the PCs?

3. How do I get the Macs and PCs to authenticate against the server and
propagate different privileges depending on whether the user is faculty,
grad student, undergrad, etc.?

4. How do I automatically log off idle machines?

5. What's the cheapest and most reliable way to back up 100-150 GB of data
on the server? I'm using Retrospect right now (which works, but I hate it)
but the tape only handles 50-60 GB compressed.

Eventually, I will want the lab monitor to be able to look at a web page and
see at a glance who is logged in at each machine, how long they have been
there, etc. I think I know how to do that part with rwho, cron, server side
includes, etc. What I need is help getting started.

Any pointers at all will be appreciated.

Thanks,
     peter

-- 
Peter C.S. Adams
Administrator of Information Technology
College of Public and Community Service
University of Massachusetts  at  Boston
"Be civil to all; sociable to many; familiar with few; friend to one; enemy
to none." -- Benjamin Franklin, Poor Richard's Almanack